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Phil_G
Guest
We were discussing how this can be done for much less than £150 and I though it worthwhile posting it as a bit of a project.
There are two cheap items to buy from ebay, this is the Sonoff switch:
Sonoff TH16A Temperature Humidity Monitor WiFi Wireless Smart Home Control HQ2 | eBay
and this is the sensor:
Sonoff TH16A Temperature Humidity Monitor WiFi Wireless Smart Home Control HQ2 | eBay
The idea is that the switch and sensor combination sits in your van, which is parked within WiFi range of your home router. The sensor is interrogated and controlled (from anywhere) by a free app on your phone.
I bought a set to try, and my Sonoff arrived this morning. It took 10 minutes to mod from mains to USB powered, I loaded the app and it all works brilliantly.
So instead of a £150 gadget that reads just temperature alone, we have temperature, humidity, and a relay you can use to remote-switch whatever you like from anywhere in the world. All for £11.44 complete
If you have your van permanently hooked up to mains then the mod isnt necessary, but I dont, so the mod simply makes it USB powered which is much more convenient.
Note that this is an either/or mod, either you connect the Sonoff to the mains supply, OR you mod it for USB power. Please dont connect a modded switch to the mains!!! If you'd like to switch mains equipment with it (via the relay) then use it as supplied, powered from the mains.
Heres a brief how-to, this converts it from mains-powered to USB-powered:
First find a dead mouse. No, a dead computer mouse! Snip off the USB plug with a couple of feet of cable. Strip the outer back an inch and there will be 4 wires, two of which are red & black. Snip off the other two.
Remove the mains terminal cover (1 screw) and the case will easily prise apart, leaving the PCB fastened to the plastic back plate with 4 screws:
Remove the PCB and remember where you put the screws. On the opposite side to all the electronics components, solder your red & black wires as follows:
Replace the PCB with the four short screws, trapping the USB lead and threading the plug through the mains connector hole.
Thats it, mount the temperature & humidity sensor somewhere convenient, plug the USB in, and you should see some LED activity. Dont worry about that for now.
Download & install eWeLink to your phone (theres a QR-code in the instruction leaflet so you cant go wrong if you scan that for the app)
Follow the eWeLink instruction leaflet to create an account & log the Sonoff into your home WiFi router.
You'll need to give the device a name - mine is called "TempHumidity"
Tap the 'name' you chose, & you'll find a real-time screen that shows temperature, humidity and an on/off switch to control your relay, which also lights the red LED on the Sonoff. When the relay is operated (ie the switch is 'on') , the screen is blue and when its not (ie switch is 'off') the screen is grey, either still shows the temperature & humidity values. The relay can be used for whatever you like, or ignored, its unrelated to the temperature/humidity monitor.
Of course we're only scratching the surface of possibilities here - you can set schedules, alarms, switch a heater on if its too cold, switch a dehumidifier on if its too damp... its very versatile. It can also integrate into 'Alexa' if you're a fan like me!
So there you go. At £11.44 you have a superdooper monitor for your van with more facilities than a £150 jobbie and the satisfaction of a tiny bit of DIY.
And £138.56 change to treat your missus to something nice!
Cheers
Phil
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